Chromatin (chicken erythrocytes) was used as substrates for the study of single-strand specific enzymes: mung bean nuclease, phosphodiesterase and nuclease P1. All three showed great similarities in producing very large fragments that were relatively long-lasting (2 to 4 hours). These fragments preserved nucleosome structure and corresponded to a superbead multimer of about 30 (with a range from 8 to 80 nucleosomes). Removal of histones H1 and H5 did not make chromatin much more susceptible to these enzymes. Ribomononucleosomes were found to be interspersed along DNA chains in crab d(A-T) polymer. 50% of all G was rG. Dinucleotides -dC-rG, -dT-rA and -dT-rG were identified. Hydrolysis with 0.3M KOH decreased the RNA content to two-thirds of the original.